Adjustable clamp



Dec. 23, 1952 E. F. FULLWOOD 2,622,831

ADJUSTABLE CLAMP Filed June 20, 1950 2 SHEETS-SHEET 1 FlG.l

L INVENTOR EDWARD FFULLWOOD ATTORNEYS Dec. 23, 1952 E. F. FULLWOOD 2,622,831

ADJUSTABLE CLAMP Filed June 20, 1950 2 SHEETSSHEET 2 39 El vl3 l2 I4 29 FIG.3

INVENTOR J G EDWARD F FULLWOOD ATTO R N EYS Patented Dec. 23, 1952 ADJUSTABLE CLAME Edward F. Fullwood, Madison, Wis., assignor to Air Reduction Company, Incorporated, Murray Hill, N. 3., a corporation of New York Application June 20, 1950; Serial No. 169,268

Claims.

This invention relates to adjustable clamps for adjustably attaching one object to. another.

My adjustable clamp was designed primarily for use on obstetrical operating tables for adjustably mounting the knee crutch on the. table, but it is not limited to this particular use and ma be used for adjustably attaching two objects of any kind.

A knee-crutch clamp must have a wide range of adjustability and must be capable of with standing large forces exerted by the patient. It usually includes a rod that. supports the knee crutch, this rod being clamped to the operating table so that the rod may be adjusted longitudinally in the clamp, rotatively adjusted about its own axis, and rotatively adjusted in a vertical plane, these three ways ofadjusting the rod making it. possible to give to the knee crutch supported by the rod the proper elevation and angularity to suit the needs of a patient.

A problem that has been encountered in devising a satisfactory knee-crutch clamp is to prevent turning of the rod within the clamp. When the rod is of" circular cross-section the clamp has sometimes been provided with serrated jaws to produce a better gripping action on the rod, but this is undesirablevbecause such jaws mutilate the rod. It is possible to enlarge the diameter of the rod so that the clamp will better resist the turning imposed on the rod, but this is often undesirable because the rod then has an excessive size and weight for its purpose. Another reason why it is not desirable tov use a large diameter rod is. that the clamp will'then not properly receive and clamp other operating table attachments havin smaller diameter rods. Another way that a relatively small diameter rod can be prevented from turning in the. clamp is to give the rod a non-circular cross-section, such as rectangular or hexagonal, and to shape the jaws of the clamp accordingly, but this prevents the desired rotary adjustment of the-rod about its axis from being obtained unless this adjustment is provided for in some other way.

The problem above described also frequently arises in connection with adjustable. clamps for adjustably connecting other objects and-that have the same general construction and adjustable features as a knee-crutch clamp. The improvements provided by this invention, although especially useful in a knee-crutch clamp, are therefore also useful in adjustable clamps of other kinds.

'The principal object of the invention, therefore, is to provide an adjustable clamp for knee 2. crutches and other uses which makes possible the secure clamping of a rod of relatively small diameter, not only against longitudinal move- 'ment but also against axial rotation, without mutilating the rod and without makin it infpossible to rotatively adjust the rod about its axis when it. is. desired to do so.

According to the invention the improved adjustable clamp. comprises a main or outer clampil'lg member adapted to be connected to one of the two objects that are to be attached by the clamp, an inner clamping member adapted to be: clamped in the outer member, and a rod adapted to be connected to, the other object and which passes through and is automatically clampedv bythe inner member when this member is clamped by the outer member. The outer member is, preferably a clamp of the resilient split-sleeve type, and the inner member is preferably a collet, retained in the split-sleeve portion of the outer member and between the jaws of'which the rod passes. The rod is made nonrotatable relative to the collet as by giving the rod and the rod-receiving space in the collet a rectangular, hexagonal, or other non-circular cross-section. However, the collet can normal- 1y turn in the'split p rtion of the outer clamping member and this permits rotary adjustment of the rod about its axis when the split sleeve is loosened as well as longitudinal adjustment of the rodin the collet. When the split sleeve is tightenedit grips the collet and prevents it and alsothe rod from rotating and at the same time forces the collet jaws into gripping engagement with the rod to hold it against longitudinal movement. The inner surface of the collet jaws may be smooth so as not to mutilate the rod because they are required to hold the rod against longitudinal movement only, smooth collet jaws being suflicient for this purpose. Even though the rod may be small in diameter it is securely held against rotation when the splitsleeve .portion of the outer clamping member is tightened because the split-sleeve portion does not clamp the rod directly but clamps the collet which may be made with an outer diameter sufficiently large to enable the split sleeve to grip and hold the collet securely, and the collet in turn prevents rotation of the rod because of the non-circular cross-sectional shape of the rod. The. clamping screw by which the split sleeve of the outer clamping member is tightened and loosened also preferably operates a clutch interposed between this clamping member and the object to'which it is attached, whereby when the split sleeve is tightened and the rod is securely clamped against longitudinal movement and axial rotation the clutch is engaged and the outer clamping member is in fixed relation to the object, but when the split sleeve is loosened the clutch is disengaged to permit rotative adjustment of the split sleeve and. rod in a plane at right angles to the axis of the clamping screw.

An adjustable clamp embodying the invention is illustrated in the accompanying drawings, in which:

Figure l is a side elevation, partly in section, of the clamp,

Fig. 2 is a top plan view of the clamp,

Fig. 3 is a horizontal section taken along line 33 of Fig. 1,

Fig. 4 is a vertical section taken along line l4-of Fig. 2,

Fig. is an end view of the collet, and

Fig. 6 is a longitudinal section of the collet taken along line S-E of Fig. 5.

Referring first to Figs. 1-3, the above-mentioned outer clamping member is shown at Ii]. In its preferred form it is of the split-sleeve type having a sleeve portion II (Figs. 2 and 3) split at one side as shown at I2 to make the sleeve portion resilient. The split side of the sleeve has a pair of extensions I3 and I4 one on each side of the split I2. A clamping screw I5 extends transversely through the extensions I3 and I4 with a slight clearance, as best shown in Fig. 3. The way this clamping screw is mounted so that when turned it will either tighten or loosen the split-sleeve portion I I will be more fully described later.

The inner clamping member is best shown at It in Figs. 2 and 3 and is preferably in the form of a collet which is shown by itself in Figs. 5 and 6. As shown in these figures the collet is generally cylindrical in shape and normally fits loosely within the opening in the split-sleeve portion II of the outer clamping member. The collet is provided at each end with an external annular groove I! (Fig. 6) in each of which is located a spring retaining ring I8. This ring slightly overlaps the upper and lower sides of the sleeve II of the outer clamping member, as shown in Fig. 1, to retain the collet in the sleeve while permitting it normally to turn therein. The collet is provided with a number of longitudinal slots to provide resilient collet jaws. There are preferably four of such slots shown at I9, 22, ZI and 22 in Fig. 5. The slots are so arranged that slots I9 and 26 are in a single plane and slots 2i and 22 are in another plane substantially at right angles to the first plane. The slots I9 and 2e are cut into the collet from its left end as viewed in Fig. 6 and terminate a short distance from the right end, while the slots ZI and 22 are cut into the collet from its right end and terminate a short distance from the left end. Thus, the collet is not completely severed through in any one plane and is therefore a unitary structure, but the walls of the collet may at all points be moved inwardly a limited distance by the split sleeve II of the outer clamping member when it is tightened by the clamping screw I5.

The collet has a central opening 23 to receive a rod 2 (Figs. 1, 2 and 3). The rod and the rod-receiving opening in the collet are non-circular in cross-section, preferably hexagonal. Thus, the rod cannot turn about its own axis Within the collet, but rotative adjustment of the rod about its own axis in the split sleeve of the outer clamping member is permitted when the split sleeve is loosened because the collet under these circumstances can turn in the split sleeve. Also, when the split sleeve is loosened the rod may be adjusted longitudinally in the collet but when the split sleeve is tightened the rod is firmly gripped by the resilient jaws of the collet and therefore securely held against longitudinal movement, and since the collet cannot now turn in the split sleeve the rod is also securely held against rotation about its own axis. The inner surface of the collet jaws is preferably smooth so that the rod is not mutilated when it is clamped by the collet.

The outer clamping member I9 is connected to one of the two objects to be adjustably attached by the clamp, and the rod 24 is connected to the other of the two objects. Since the particular clamp shown in the drawing was designed especially for supporting a knee crutch 'on an operating table, the object to which the outer clamping member IE1 is connected is shown in Figs. 1, 2 and 3 as a side portion 25 of an operating table, and the upper end of the rod 24 is shown bent at right angles to the portion of the rod which passes through the collet as is customary in adjustable clamps for supporting knee crutches and other accessories over an operating table. The knee crutch (not shown in the drawings) is connected to the upper extremity of the rod at 21.

In the particular adjustable clamp shown in the drawings the clamping screw I5 constitutes part of the means by which the outer clamping member It is connected to the side 25 of the operating table. A bracket 28 is secured to the side of the operating table by screws 29 as best shown in Figs. 2 and 3. The threaded end 30 of the clamping screw engages in an interiorly threaded sleeve 3I (Fig. 3). This sleeve has a peripheral flange 32 at its end nearest the operating table which engages a shoulder 33 formed in the bracket 28. The sleeve BI is held against rotation in the bracket by means of a pin 34 (Fig. 4) which constitutes a key between the sleeve and the bracket 23. The outer end of the clamping screw I5 has an enlarged portion 35 (Figs. 1, 2 and 3) carrying a handle 36 by which the clamping screw may be manually rotated to thread it into or out of the sleeve 3I. The enlarged portion of the clamping screw bears against a suitable thrust bearing 3'! housed in a retainer cup 38 and interposed between the enlarged portion of the clamping screw and the outer face of the clamping member I6. Thus, when the clamping screw is rotated to thread it into the sleeve 3I the enlarged end 35 on the clamping screw is moved toward the sleeve (H and the extensions It and I4 on the split sleeve are moved closer together to contract the splitsleeve portion II of the outer clamping member against the collet I6. When the clamping screw is rotated in the opposite direction the split-sleeve portion of the outer clamping member is expanded to free the collet so that it can be rotated.

Positioned concentrically on the sleeve 3| between the bracket 28 and the inner face of the outer clamping member I0 is a clutch, one member 39 of which is pinned to the bracket as shown at 40 (Fig. 3), and the other member M of which is pinned to the outer clamping member as shown at 42. The meeting faces of the two clutch members are preferably toothed or serrated as best shown at 43 in Fig. 1. When the clamping screw is tightened the two clutch members are engaged,

i. e., the teeth on the two clutch members are in meshing relation, and the outer clamping member Hi is then firmly held against rotation about the axis of the clamping screw 15. The outer clamping member It may be moved outwardly along the axis of the clamping screw when the clamping screw is partially unthreaded from the sleeve 3!. This disengages the clutch members 39 and M. The outer clamping member Iii may then be turned about the axis of the clamping screw E5 to another position as indicated in dotted lines in Fig. 4. The clamping screw may be turned enough to release the grip of the split sleeve on the collet and to permit rotative adjustment of the rod 24 without disengaging the clutch members 39 and ill.

It will now be seen that when the clamping screw [5 is threaded into the sleeve 3| a sufficient distance the collet is firmly gripped in the splitsleeve portion of the outer clamping member and this holds the collet and hence the rod 24 against rotation about the axis of the rod and it also collapses the collet so that the collet jaws grip the rod and hold it securely against longitudinal movement in the collet. Moreover, the outer clamping member is held against rotation about the axis of the clamping screw i5 by engagement of the clutch members as and 4!. When the clamping screw is unthreaded from the sleeve M a small amount the split-sleeve clamp releases its grip on the collet and the rod 24 can then be rotatively adjusted about its axis, since the collet can now turn with the rod. Thus the bent extension 26 on the rod can be turned to any angular position such as that indicated by the dotted lines in Fig. 2. Moreover, the rod can be adjusted longitudinally in the collet and if the clamping screw is unthreaded from the sleeve 3| far enough the clutch members 39 and M can be disengaged so that the outer clamping member may be turned about the axis of the clamping screw to permit adjustment of the rod 24 in a plane at right angles to the axis of the clamping screw.

The use of a collet or an inner clamping member for the rod, positioned within and clamped by an outer clamping member, makes it possible to employ a rod of relatively small cross-section because the inner clamping member can bemade sufiiciently large in diameter to enable the outer clamping member to grip it securely and when the inner clamping member is thus gripped the rod is securely held against rotation about its axis without the employment of serrated jaws which would be necessary to obtain a firm grip on a small rod of circular cross-section and which would tend to multilate the rod.

I claim:

1. An adjustable clamp for adjustably attaching one object to another comprising a clamping member for attachment to one of said objects and having a collet-receiving opening, a collet retained in said opening, a rod for attachment to the other of said objects and extending into said collet and being axially non-rotatable with respect thereto, and means for actuating said clamping member, clamping of the collet in the clamping member serving to clamp the collet jaws against said rod and hold it against longitudinal movement in the collet and also serving to prevent rotation of the collet and hence axial rotation of the rod, and release of the collet by the clamping member permitting longitudinal adjustment of the rod in the collet and axial rotation of the rod.

2. An adjustable clamp for adjustably attaching one object to another comprising an outer clamping member for attachment to one of said objects and having a cylindrical opening, an inner clamping member retained in said opening, the outer clamping member having clamping portions movable inwardly to clamp the inner clamping member in the opening of the outer clamping member, means for actuating the outer clampin member to clamp or release the inner clamping member, the inner clamping member when released being rotatable in the cylindrical opening of the outer clamping member, the inner clamping member having a rod-receiving opening, a rod for attachment to the other of said objects and extending into said opening in the inner clamping member and being axially non-rotatable with respect to the inner clamping member, and the inner clamping member having clamping portions adapted to be moved inwardly by the clamping of the inner member in the outer member to thereby clamp the rod in the inner member and hold it against longitudinal movement, whereby when the inner clamping member is clamped in the outer clamping member the rod is held against both longitudinal movement and rotation about its own axis and when the inner clamping member is released by the outer clamping member the rod can be longitudinally adjusted and also rotatively adjusted about its own axis.

3. An adjustable clamp in accordance with claim 2 in which the outer clampin member is of the split-sleeve type havin a sleeve portion split at one side to make the sleeve resilient, and the inner clamping member is a collet retained in the split-sleeve portion of the outer clamping member.

i. An adjustable clamp in accordance with claim 3 in which the portion of the rod that extends into the collet is non-circular in cross-section.

5. An adjustable clamp for adjustably attaching one object to another comprising a bracket adapted to be attached to one of the objects, a clamping member supported by said bracket and having a sleeve portion split at one side to make the sleeve resilient, the split side of the sleeve having a pair of extensions one on each side of the split, a clamping screw passing through said extensions at right angles to the axis of the sleeve opening, a collet retained in the opening of the sleeve, actuation of said clamping screw serving to clamp the collet in the resilient sleeve or to release it, said collet when released being rotatable in the openin of the sleeve, a rod for attachment to the other of said objects and extending into said collet and being axially non-rotatable with respect thereto, clamping of the collet in said resilient sleeve serving to clamp the collet jaws against said rod and hold it against longitudinal movement, and a clutch interposed between said bracket and said clamping member adapted when engaged to hold the clamping member in fixed relation to said bracket and when disengaged to permit rotation of the clamping member about the axis of the clamping screw, said clutch being controlled by the clamping screw, whereby turning of the clampin screw in one direction engages said clutch to hold the clamping member in fixed position and clamps the collet in the resilientsleeve portion of the clamping member to thereby hold the rod against rotation about its axis and against longitudinal movement, and turning of the clamping screw in the opposite direction per- 7 mits longitudinal adjustment of the rod in the pellet and rotation of the rod and collet about the axis of the rod and rotation of the rod in a plane at right angles to the axis of the clamping screw.

EDWARD F. FULLWOOD.

REFERENCES CITED The following references are of record in the file of this patent:

Number Cox Aug. 8, 1950 

